As a typical flat display device, for example, a liquid crystal display device includes a liquid crystal display panel equipped with a liquid crystal layer held between a pair of substrates. One substrate includes a plurality of picture electrodes arranged in the shape of a matrix, a plurality of scanning lines extending along with row lines of picture electrodes, and a plurality of signal lines along with column lines of the picture electrodes. The other substrate includes a common electrode opposing to the picture electrodes.
The one substrate further includes a gate driver which drives the scanning lines. A circuit board is electrically connected to one end of the substrate through a flexible substrate. A source driver (IC) which supplies picture signals to the signal lines is mounted on the flexible substrate.
The number of signals outputted in parallel from the source driver changes according to the number of the signal lines. In recent years, the number of signals outputted from the source driver increases with the demand for a high definition display, and the output terminals are provided not only in an edge located at an output side of the source driver but in an edge located at an input side of the source driver. In general, the source driver is formed so that the actual number of the output signals of the source driver is changeable by using some of the output terminals formed in the source driver. When all of the output terminals formed in the source driver are used, the output terminals formed in the input and output sides are set by denoting the respective one end and the other end of the output terminals as a starting terminal and a terminating terminal.
Here, the output wiring extending between the output terminals formed in the edge of the input side of the source driver and output terminals of the flexible substrate is pulled out by bypassing the short edge side of the source driver. If the output wirings are arranged so as to bypass in the vicinity of the short edge side of the source driver, a flexibility for designing the output wiring in a region between the short edge side of the source driver and an end of the flexible substrate is reduced.
Conventionally (referring to Japanese laid open patent application No. P2006-23469), the output wirings are pulled out from output terminals formed in the edge of the input side of the source driver to the output side of the source driver by passing under the source driver to make the flexibility for designing the output wirings in the vicinity between the short edge of the source driver and the end of the flexible substrate where the source driver is arranged. According to this method, it becomes possible to enlarge the flexibility for designing the output wirings in the vicinity of the region between the short edge of the source driver and the end of the flexible substrate.
However, if the output wirings are pulled out from the output terminals arranged at the input side to the output side of the source driver by passing under the source driver on the flexible substrate, the pitch between the wirings pulled out from the output side and the input side of the source driver becomes narrower, which sometimes results in difficulty in the arrangement of the wirings.
Furthermore, even if there were fewer output signals which are outputted to the signal lines than the total number of the output terminals of the source driver, the starting position of the output terminals is set to one end of the output terminals arranged along with the edges of the source driver, and the terminating position is set to the other end of the output terminals.
Therefore, even in this case, since the output wirings are pulled out in the vicinity between the short edge of the source driver and the end of the flexible substrate where the source driver is arranged, the design flexibility of the flexible substrate falls, and further, the flexible substrate may become large, which results in the difficulty in reducing a manufacturing cost.